Door switch wiring
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Post Fiend
Joined: May 2006
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From: Central Florida
Door switch wiring
The truck is a 2002 F250 Superduty crew cab, lariat, ect. My problem is. With either or both doors closed the door ajar light comes on. The only way to turn the light off is to open both front doors.
The switches apparently work because they can deactivate the light. I believe the switch sends a grounds when they are closed. So what I am thinking is the module is getting ground when the switch is open and when either or both switch is close it's getting power.
Which leaves me to believe that there is a common ground for the front doors that has another accessory shorting into it. So does anyone know where the front door switches ground?
The switches apparently work because they can deactivate the light. I believe the switch sends a grounds when they are closed. So what I am thinking is the module is getting ground when the switch is open and when either or both switch is close it's getting power.
Which leaves me to believe that there is a common ground for the front doors that has another accessory shorting into it. So does anyone know where the front door switches ground?
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Joined: Jan 2001
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From: Virginia
You are correct, the door switches ground a wire that goes to a body module. Then the body module communicates over the network to the microprocessor in the instrument cluster.
I know these switches have a lot of problems sticking, and I guess you already know about the wd40 in the latch trick.
I am following you on your ground theory, but to make sure you are going down the right path, you may want to get a scrap piece of wire and bolt it to a known good ground, and then touch it on a part of the door and see if it helps or makes any difference. I don't have my diagrams with me right now to see where the ground is located for the door wiring.
I know these switches have a lot of problems sticking, and I guess you already know about the wd40 in the latch trick.
I am following you on your ground theory, but to make sure you are going down the right path, you may want to get a scrap piece of wire and bolt it to a known good ground, and then touch it on a part of the door and see if it helps or makes any difference. I don't have my diagrams with me right now to see where the ground is located for the door wiring.
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Post Fiend
Joined: May 2006
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Likes: 4
From: Central Florida
The switches are new, I replaced them a couple of months ago while working on this project. They do work because I can cause an effect by closing one or both doors. It's something in the wiring.
No other problems in the door and I checked the drivers side today while I had the kick panel off. The bolts on the door show no power and good ground. I was hoping to find a bolt with several grounds and showed a slight current, but I only found one ground with one wire on the drivers side kick panel.
The rear doors don't trip any circuits so it's not a ground problem that extends to them unless they are sending an always grounded. I can't find any links between the front door problem and the rears not working at all, so I am trying to tackle it one problem at a time until something new happens.
No other problems in the door and I checked the drivers side today while I had the kick panel off. The bolts on the door show no power and good ground. I was hoping to find a bolt with several grounds and showed a slight current, but I only found one ground with one wire on the drivers side kick panel.
The rear doors don't trip any circuits so it's not a ground problem that extends to them unless they are sending an always grounded. I can't find any links between the front door problem and the rears not working at all, so I am trying to tackle it one problem at a time until something new happens.
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Joined: Jan 2001
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From: Virginia
I replaced them a couple of months ago while working on this project.
The module recognizes "ground" when the door is opened, but it doesn't really know what "ground" is unless it's grounded properly itself.
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Post Fiend
Joined: May 2006
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From: Central Florida
By project I mean getting it to work properly again, the truck is clean. Several years ago while getting an oil change the VSM died, I replaced it and got my keyless entry working again. I am still stuck with the door lights staying on, though. I have replaced 2 of the switches, the VSM and cluster and let ford charge me to program it all.
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Joined: Jan 2001
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From: Virginia
I looked in the diagrams, and it seems the ground for the driver's side door is located in the driver's side back corner of the cab, about half-way up the pillar. They made no distinction about a 4 door or a 2 door, so I assume yours is there too. Looking at the picture, it's very close to the lower corner of the back window.
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Post Fiend
Joined: May 2006
Posts: 10,007
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From: Central Florida
It's not in the back on a crew cab. I followed the black wire on the right rear door switch forward to between the A/C box and the side of the kick panel where I couldn't follow it any further. There is no continuity between either of the contacts and the body, so there must be a ground a problem.
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FTE Legend
Joined: Jul 2005
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From: Millersville, MD
So just ground it somewwhere along the way...cut wire, strip insulation attach (I would solder) wire to a terminal and screw it to another existing ground point or make your own.
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Thread Starter
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Post Fiend
Joined: May 2006
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From: Central Florida
Neither rear is working, and the fronts can shut off the light if both are open. I found a large ground on the drivers side, and three more in the bundle in the door sill. All three check out to the seat belt brackets. The pass rear door should be grounding correctly but it's not triggering anything. I even tried sending a ground from the switch harness on the pass rear door from the seat belt bolts to the signal wire with no effect.
I am lost diagnostically, short of taking all four doors loose and shorting each switch to the body. Any help?
I am lost diagnostically, short of taking all four doors loose and shorting each switch to the body. Any help?
